Driving mechanism for power lawn mowers



H. L. BLYDENBURGH DRIVING MECHANISM FOR POWER LAWN MOWERS Aug 15,1950

2 Sheets-Sheet 1 Filed June 25, 1948 Zinnentor H. L. BLYDENBURGH DRIVING MECHANISM FOR POWER LAWN MOWERS- Aug. 15, 1950 Filed June 25,- 1948 2 Sheets-Sheet 2 tornegs Patented Aug. 1 5, 1956 OFFICE DRIVING MECHANISM FOR POWER LAWN MOWERS,

' Harold L. Blydenbungh, Detroit, -Mich., assignor to The Mote-Mower Company, Detroit, Mich. a corporation of Michigan 1 Application June 25, 1948, Serial No 35220 6 Claims.

invention relates to power lawnmowers and, in particular, to driving mechanism for power lawnmowers.

f One object of this invention is to provide a powerlawnmower driving mechanism which will be" free from any tendency to pull the cutting reel into the ground on the driving side and cause uneven cutting, as in prior power lawnmowers.

Another'jobject is to provide a power lawnmower drivingmechanism wherein the drive to the cutting reel is transmitted thereto from a shaft journaled on the cutting reel frame rather than on the lawnmower frame, thereby preventing the above-mentioned pulling effect upon the cutting reel. i

Another object is to provide a power lawnmowerdriving mechanism,wherein the cutting reel is journaled in "a cutting reel frame which in'turn is pivotally connected to the lawnmower frameso as to rise and fall as it traverses uneven ground, the driving force being transmitted from the lawnmower frame to a countershaft j ournaled onthe cutting reel frame so as to "rise and fall therewith, the 'countershaft'in turn being drivingly'connected to the cutting reel for the purposes" above set forth.

In the drawings:

Figure 1 is a top plan view of a power lawnmower; equipped with an improved driving mechanism according to a preferred form of the in- -Figure' 2 is aside elevation' of the power lawn-- mowershownin Figure 1-;-and i Figure 3 is a front elevation of the power lawnmower shown in Figures 1 and 2.

Hitherto, the cutting reels of certain types of power lawn mowers have been journaled in a cutting reel frame, which in turn is pivotally connected to or mounted upon the power lawnmower frame so as to rise and-fall as the cutting reel traverses uneven ground. The cutting reel has frequently been driven hitherto by an endless belt' or sprocket chain extending from a pulley or sprocket on the cutting'reel shaft to a pulley or sprocket on the lawnmower frame. Since the two shaftsjhave ordinarily been separated by a considerable distance. thereby requiring a relatively long belt or sprocket chain, the force exerted by this chain pulled the cutting reel into the ground on the driving side because the lower section of th 'belt or chain was in tension and hence createdan underpull upon the cutting reel pulley or sprocket. This; in turn tended to cut the grass close-to" the ground-on the driving side of the cutting reeL-thereby creating a groove-or ridge in the grass on the'driving side of the cutting reel. This ridge or groove is quite noticeable and is sometimes very unsightly.

The present invention eliminates this underpull upon the cutting reel pulley or sprocket and thereby gets rid of the unequal thrust exerted uponthe cutting reel frame on the driving side of the cutting reel. The invention eliminates the previous direct drive from a shaft on the lawnmower frame through a long endless belt or sprocket chain to a sprocket on the end of the cut-- ting reel-and accordingly eliminates the unequal torque effect resulting therefrom and tending to tilt the cutting reel frame downward on the driving side. The invention does this by driving to a countershaft on the cutting reel frame and thence to the cutting'reel shaft, eliminating any possi* bility of relative motion between the two pulleys or sprockets, since both move up and down as a unit.

Referring to the drawings in detail, Figures 1- to 3 inclusive show a power lawnmower, generally designated l9, equipped with the improved driving mechanism of the present invention and consisting generally of the main portion or tractor portion ll of the lawnmower and the cutting reel assembly I2 pivotally connected thereto. Themain or tractor portion ll consists of a lawnmower frame generally designated l3 having a handle I4 pivotally connected as at 15 to the rearward end thereof and having downwardly extending bearing assemblies IS in which is journaled the axle l1. Ground wheels l8' with tires [9 are mounted on the opposite ends of the axle I1 and have hubs 20 carrying sprockets 2| circled by sprocketchains 22.

The sprocket chains 22 in turn encircle sprockets 23 mounte'd on a shaft 24 supported in bearing brackets 25 extending upward from and bolted to a frame cross-member 26. The shaft 24is journaled in a base structure 21 mounted upon the frame l3 and carries a third sprocket 28 which is drivingly'connected to a, sprocket 29 by a sprocket chain 30. The sprocket 29 is mounted upon the output shaft 3| of a reduction gear set 32, the input shaft 33 of which is the crankshaft of a conventional internal combustion engine 34. The latter is bolted to the base struc-- ture 21. The showing of the engine 34 and output shaft 3| as directly'connected to the shaft 24 is conventional and simplified for clearness of showing. Ordinarily, one or more clutches areinterposed between the shafts 3| and 24 in order to interrupt the drive, these'clutches having been:

omitted for that reason.

nected as at to the lower end of a hand lever 41 which in turn is pivotally nounted as at 42 on a bracket 43 bolted to the lawnmower frarne I3. The bracket 43 carries a ratchet-toothed quadrant 44 which is engaged by a pawl .45 ply:

otally mounted on the pivot pin 4 0 and connected 1 by a link 46 to a push button 4! in the upper end of the hand lever 4|. A coil spring 48 constantly urges the push button 41 and'link 46 upward, constantly urging the pawl into holding en: gagement with the teeth 44. As is subsequently eshh heel -elew, he hem; leterit ie the Pute e e e f tei e eh l e i the e ttihe. F95

sembl'y l2.

h h hntee en the ivot th t 35 the e "e ethe dl ene etw d theref elh s lhhet hehe le em ig-e 7 te the thrwe el 'eneee Whieheee et rhembet 50 s etret t e t eh d et e hee ehet m mtet me t e e t rhe en e uh etee ieint t?! the 5 he er hel h rt h 'ti .ef wh h is m unted ej belt, 54 .m htest eh 'ehe es wee a air e ewetely-dhee ed a ms .l a he arm 5 eee eeh tee the steh l e werel h el theehpet Y 1'1 '4 l f eeeiwe h he e of t e end ieee it letter cross members 59 and 60 respectively. Ordie h isth e eve et extehee het eeh he tre h tere 9 ehd it t9 e ee t eh t he r l ehsl the 'her eheet Thte eei et plate is eetee et 5'! h eete but he teeth e ie F u e 1 th m 9 e ei eehe e l 'ele hee h i hQ ie ee 1 e e! A i tthe erect 9 the 49 1 ere h ht eleehee b h hr li'eh the in e ler 'te s ew the dh he ee h heheeth ithel ee'te heehe ele ee ee eh e e it e d 9 the ee t he ree ehe Pl es 2:" These reeeh eheelet h eiezhe l e here eer e heeeee e tt i net si es he e eh eh e e 5 .1 'E eh he l terel eether eh ethelee i the tense heeeee' 5e 1e.

hai t of e eh ihs reel seher 11 dee het s 65, h vin p r l l de ee thei htesi eh-the eei a P el e helt e te the. ehel Plate 5? an htehdih between t e-t is e eutter te eeee et item h e elete edg .4 he e e l ee eh te h t nrei ets e we el o eleee PFQX: ter the eht ihe ed es 9? th shi e! lades ee- Th ehs pl e t? ar else mende w th t th ha dl ext ndi ess er ear .9 whieh are f??? tie h eree-vee e re e the e d 1e s te -tee t ete M u ed in he evee; ehee hi the h hreekete 1 l is the a le 9 thest uhs elle 1. Whieh e u tes the .dis eheeet W eh t l h tihe ee e e Qt th eetter ha e 69 eh lhee blah ee tte e eehee eently reshl tne the ight at h eh the ee is e itbutton 4? on the hand lave ga ethe trawl 5 hen; the ratchet Quad ant .44.

, e he ehre het ehaih ting over the ball-headed bolts 19. The latter are mounted in the lower ends of brackets (Figure 2) extending downward from the lawnmower frame cross member 26 and bolted to the underside thereof. Thus, by the links 11 and the arm 49, the cutting reel assembly [2 is pivet l y co n cted t e main Pet-@01 of the lawnmower It}.

In order to drive the cutting reel 65, a sprocket l is mounted upon the shaft 24 (Figure 2) and, V by means of a sprocket chain 82, drives a sprocket 83 mounted on a stub shaft 84 which is journaled in a bearing bushing 85 at the forward end of the left=hang1 bracket 25. Mounted on th end of the stub shaft 84 is a universal mint :35 to which is connected a tubular shaft 81 having one or more longitudinal slots 88 therein. Telescoping into the tubular shaft 88 is a shaft 83 having a driving pin 96 engaging the slots 88 and furnishing a driving yet sliding connection between he fts l and {19- Cehheetee t9 t hh end of th the t 9 i a ee joint 9! which in turn is mounted on the inner e ef e euh eheit e? ieet e e b ehh e ee 3 e the timer eh ee 3 he ehe it re e e'ti ed .h -U= l 5 t9 t e me h e 5t an 1 5 eep e tivel ifi'islhe 3 u e n he 9 4 L n e t e feet ht heit 92 a s mek t 5 Wh eh ht v'e e e te het 8 m the pu ting r e sha t 6-! h meeh hie e eehet.

chain 98. "Th s theeehhter he t 32 is haunted h the eutt he reel-heme fleets te me e he an se w hi he th et ine hee l meves over ehel etthe e ehhe -ih =9tt ehhtt 92 is driven froni the inner end thereof approxr m el et h e hteret he eu tihs l ,ej 'eh a b h e ee ehih sh ts 31,83 th re s no yn= h l e el e e phliee th the d vin ehe s t the e ine ee t eh 'eeheleehe n ee in r fleeing o th trees e sre ihiq occurs 'd rih use.

h h eti n Qt the i ention beli ved te. e elf-ev de t from the .fere et ee eriri iq hence a brief summary will sfiifice, the n na eemh eti h we: he is t rte epete hem and th he eeeer let h het-ehewm closed, the output shaft 3] of .the ge ar 199;; drives the shaft 24 by means the sprockets it e it e d t e eh eehet them t", the h s a t 4 t rn tt e th reeted wh els L8 v t h h th e het flen Z'l' e ie-the eh eehet chain ZZ. This causes the lawnmower lg to evel forwa d ene eits heweh sheet by the hand of the ope M other t9 hu st ers the the e-t9; eeh eeses th 4 so as he 135 H li e the hand lever for-ward s as to wihs h a h 59 ele hwer and lewer t e e i hs reel ass m !'2 hht l t e. ro nd holler -13 I eeehee the 'ei eehe- M g littl the sheit 'll! has een driv n he ethh ewaft e l theeu hthe-shmek ts ill. andfii an the sh eehet ehaih he the d iveheih com: hi ieete t the veee iteh :12 Fi ure 1) th m he teleee hins e1 8.9. .threugh the htv e l ieihts fit hhdtlrotation i the h tereh t t? exist the eehs qh ht m atien hi he shteehe ee meehted the hitter and there: t dr v the ehtt hs reelrs ehe let eib means Thus the .,..t? 5 retate teu tihsth ras etweh t e-ed es. f its u tin blades filte ed-the euttehh ea.

As re iee l etatee .eehheeti n with the eh n tieh ef the ,ihvehtte .s hee he eoh terr. heit 9. is wanted heQh th s PQQL heme ting reel assembly l2 downward, as inprior lawn-' mowers where the cutting reel shaft is driven directly by a sprocket chain or belt from apulley or'sprocket mounted on the lawnmower frame. As a consequence, there is no grooving or ridging of the grass or ground, and an even and smooth mowing job isperformed. It will be observed from;Figure 1 that theouter end of the triangular arm 49 is positionedslightly 01f center relatively to. the middle of, the cutting reel 65. The purpose of this oil-center suspension of the cutting reel assembly l2 by the universal joint 52 is to compensate for the slightly greater weight of the cutting reel assembly -l2' at the drivin'g end thereof because of the weight of the unbalanced driving mechanism not present at the other end of the cutting reel unit l2. Since the drive shaft 92 is mounted on the cutting reel unit [2 itself, no relative motion can occur between the shaft 92 and the cutting reel shaft 64, other than pure rotatory motion, hence there is no pull exerted by the sprocket chain 98 which acts as an underpull to pull the driving end of the cutting reel assembly l2 downward into the grass or ground.

What I claim is:

1. A power lawnmower comprising a wheelsupported cutting reel unit having a rotary cuting reel thereon, an independent wheel-supported power driven tractor unit carrying a prime mover drivingly connected thereto, said units being disposed one behind the other in tandem relationship, tie members pivotally interconnecting said units, and a cutting reel driving mechanism comprising a countershaft journaled on said cutting reel unit, said countershaft being composed of a pair of shaft sections connected by a universal joint, mechanism including driving and driven wheels on the countershaft and cutting reel respectively, and an endless flexible driving element drivingly connecting one end of said countershaft to the cutting reel, and mechanism drivingly connecting the other end of said countershaft to said prime mover.

2. A power lawnmower comprising a wheelsupported cutting reel unit having a rotary cutting reel thereon, an independent wheel-supported power driven tractor unit carrying a prime mover drivingly connected thereto, said units being disposed one behind the other in tandem relationship, tie memberd'pivotally interconnecting said units at their opposite ends, and a cutting reel driving mechanism comprising a countershaft journaled on said cutting reel unit,'said countershaft being composed of a pair of shaft sections connected by a universal joint, mechanism including driving and driven wheels on the countershaft and cutting reel respectively, and an endless flexible driving element drivingly connecting one end of said countershaft to the cutting reel, and mechanism drivingly connecting the other end of said countershaft to said prime mover, the universal joint connecting said shaft sections being located centrally of said cutting reel unit.

3. A power lawnmower comprising a wheelsupported cutting reel unit having a rotary cutting reel thereon, an independent wheelsupported power driven tractor unit carrying a prime mover drivingly connected thereto, said units being disposed one behind the other in tandem relationship, tie members pivotally interconnecting said units at their opposite ends, a central couplingstructure mounted on the central portion of said tractor unit and pivotally engaging the central portion ofsaid cuttin reelunit, and a cutting reel driving mechanism comprising a countershaft journaled on said cutting reel unit, said countershaft being composedof apair-of shaft sections connected by a uni'-' versal joint, mechanism including driving and driven wheels on the :countershaft and cutting reel respectively, and an endless flexible driving element drivingly connecting one end of said countershaft to the cutting reel, and mechanism drivingly connecting the other/end of said countershaft to said prime mover, the universal joint connecting said countershaftsections be-' ing located adjacent said central coupling.

4. A power lawnmower'comprising a wheelsupported cutting reel unit having a rotary cutting reel thereon, an independent wheelsupported power driven tractor unit carrying a prime mover drivingly connected thereto, said units being disposed one behind the other in tandem relationship, tie members pivotally interconnecting the lower portions of said units at their opposite ends, a central coupling structure mounted on the upper central portion of said tractor unit and pivotally engaging the upper central portion of said cutting reel unit, and a cutting reel driving mechanism comprising a countershaft journaled on said cutting reel unit, said countershaft being composed of a pair of shaft sections connected by a universal joint, mechanism includin driving and driven wheels on the countershaft and cutting reel respectively and an endless flexible driving element drivingly connecting one end of said countershaft to the cutting reel, and mechanism drivingly connecting the other end of said countershaft to said prime mover, the universal joint connecting said countershaft sections being located adjacent said central coupling.

5. A power lawnmower comprising a wheelsupported cutting reel unit having a rotary cutting reel thereon, an independent wheel-supported power driven tractor unit carrying a prime mover drivingly connected thereto, said units being disposed one behind the other in tandem relationship, tie members pivotally interconnecting said units at their opposite ends, a central coupling structure mounted on the central portion of said tractor unit and pivotally engaging the central portion of said cutting reel unit, and a cutting reel driving mechanism comprising a countershaft journaled on said cutting reel unit, said countershaft being composed of a. pair of shaft sections connected by a universal joint, mechanism including driving and driven wheels on the countershaft and cutting reel respectively, and an endless flexible driving element drivingly connecting one end of said countershaft to the cutting reel, and mechanism drivingly connecting the other end of said countershaft to said prime mover, said last mentioned mechanism including a telescoping shaft drivingly interposed between one of said pair of said countershaft sections and said prime mover, said telescoping shaft having a universal joint at one end drivingly and floatingly connecting said countershaft and prime mover.

6. A power lawnmower comprising a wheelsupported cutting reel unit having a rotary cutting reel thereon, an independent wheel-supported power driven tractor unit carrying a prime mover drivingly connected thereto, said 

